HTTP Status Codes

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Three digit numbers that tell you what happened with your request.

The ranges

Common codes

2xx - Success

• 200 OK - It worked. Standard success.
• 201 Created - Resource created (usually POST response)
• 204 No Content - Success, but nothing to return (common for DELETE)

3xx - Redirection

• 301 Moved Permanently - URL changed forever
• 302 Found - Temporary redirect
• 304 Not Modified - Cached version is still good
• 307 Temporary Redirect - Like 302 but keeps HTTP method

4xx - Client errors

• 400 Bad Request - Malformed request. Check your JSON/params.
• 401 Unauthorized - Not authenticated. (Should be called “Unauthenticated”)
• 403 Forbidden - Authenticated but not allowed.
• 404 Not Found - Resource doesn’t exist.
• 405 Method Not Allowed - Wrong HTTP verb
• 409 Conflict - Conflicts with current state
• 422 Unprocessable Entity - Valid JSON but semantically wrong
• 429 Too Many Requests - Rate limited. Slow down.

5xx - Server errors

• 500 Internal Server Error - Generic “something broke”
• 502 Bad Gateway - Proxy couldn’t reach upstream
• 503 Service Unavailable - Server overloaded or down
• 504 Gateway Timeout - Proxy timed out

Common confusion

401 vs 403:

• 401 = “Who are you?” (need to log in)
• 403 = “I know who you are, but no” (logged in, not authorized)

400 vs 422:

• 400 = Can’t even parse your request
• 422 = Parsed it, but the data is invalid

Quick debug guide

Glossary

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